All 5 entries tagged Nuclear

October 30, 2013

Unless you are living on Mars, you will have noticed a great deal of news coverage and political froth on energy supply recently. I thought I would set out the lay of the land as I see it in an attempt to try and cut through some of what has been reported.

Energy prices have increased significantly above inflation since 2007, when we all started to become poorer as a result of the credit crunch and hence have been sensitive to cost of living increases. Those cost increases are down to a number of pressures:

The cost of fuel is increasing. This is in turn driven by a number of factors which include increased demand from emerging economies, finite reserves depleting making extraction more expensive, and fuel being traded internationally when the pound has significantly weakened. Roughly speaking, the wholesale cost of energy makes up around 45% of a domestic bill, and has been responsible for about 60% of the cost increases to the consumer.

The transmission costs for the UK networks are increasing above the rate of inflation. This is because of the need to create a lot of new infrastructure for gas storage and connection of renewables to the grid. Transmission costs make up about 20% of a domestic bill, and are responsible for around 15% of the cost increases.

There are a range of environmental subsidies which are all paid for through levies on domestic bills. You have probably noticed the large numbers of solar panels springing up on rooftops and in fields, or the construction of lots of new wind turbines. All of these are subsidised through feed-in tariffs, which come out of bills. Then there are smart meters and energy efficiency measures like “free” loft insulation. This is “free” at the point of use, but your energy supplier does this at zero cost to themselves – it’s all paid for through these levies. Additionally, a carbon price has come into force. This makes up around 5% of the gas pricel and 30% of the electricity price, and starting from a zero base a few years ago this is entirely a cost inflationary aspect.

Following privatisation and subsequent botched market reforms, the price of energy collapsed around the turn of the millennium. We were therefore starting from a very low base, where energy was cheaper than it sustainably could have been. The energy companies were essentially all broke (sob sob I hear you cry…) and as a result of this and a lack of a clear long term direction for the sector set by policy there has been no driver to invest in new plant. We are now at the point where old stations that were build during the state industry days need replacing or are being forced to close due to new regulations. In order to invest in plant, energy companies need to raise the cash and demonstrate a reasonable rate of return to investors.

You will notice that none of these drivers are “trying to make a quick buck”. The headlines you read about profit margins are often misleading, to say the least. The energy market is volatile so it is only to be expected that year on year sometimes profits will jump up and sometimes they will fall back. In 2012, the company I work for (EDF Energy) saw profits fall by about 6%. A lot of our profits are also going into building new stations, covering investment in our existing plant (for example, post-Fukushima upgrades to our nuclear fleet) and covering other costs such as pension deficit repairs. The actual bottom line figure is much lower than the headlines suggest. Companies have to make a reasonable profit in order to be sustainable for the long term, otherwise you get market instability and a lack of investment. Healthy companies mean stable employment for a large sector of the UK workforce, and good returns for investors. A large chunk of institutional investors are actually pension funds of the UK workforce, so I suspect it’s in many of our interests that a reasonable return is given to them otherwise our retirement suffers.

To be fair, the coverage I have read on the BBC is largely quite balanced and communicates the above information in a balanced way, if you care to look for it. Newspapers have their own agendas and will tend to follow the direction of the political parties they support, and in any case love to stir up a story of public outrage. Whilst this is disappointing, there’s not much that can be done about it. What irks me though is that politicians who must surely be in the know about all these facts have decided to play political football with energy prices as we all seem to have moved on from blaming banks for our present troubles. A great example of this is Ed Miliband’s price freeze policy.

Whilst the price freeze may gain a lot of popular support from hard-up voters who aren’t all that well informed or interested in the nuances of the energy markets and only see rising bills and the finger being pointed at “the big six”, it presents a completely false picture of what is happening in the market. We are at a crunch point where we need to spend well over £100bn in the coming years on new energy infrastructure, and the government is looking to the private sector to fund this. The bill is much larger due to the environmental pressures being exerted on the industry – by the politicians. And into this delicate climate where we are being asked to spend vast sums on new plant (with a rather unstable outlook), in wade the politicians with all guns blazing for a few cheap headlines. You couldn’t make it up. If you want to freeze your energy prices for 20 months, you can already do so anyway without the need to go to the ballot box – just switch to a long term price fix contract, which are available for up to 3.5 years in length. John Major with his support for a windfall tax is no better – what sort of message is that sending? Please invest all these billions of pounds in projects that take decades to pay back, but don’t you dare make any money out of it or we’ll just shift the goal-posts and tax you at a moment’s notice. Or maybe all these environmental obligations we’ve been working on for years, perhaps we’ll just scrap them and upset the apple cart on all your investment planning.

With this kind of unstable climate, all that you will do is scare off investors and we won’t have any new infrastructure. As a result, we will see long term prices continue to rise whilst becoming increasingly unstable and the threat of a capacity shortfall will increase. That’s good for no-one. What is needed is a sensible and grown up approach, the outlook for which until the 2015 election does not look hopeful.

This brings me neatly on to the new nuclear deal at Hinkley C. The coverage centred on the strike price, and rightly so. The price agreed is lower than existing costs for all other low carbon technologies, so it should be a good deal for consumers. As I understand it, the price is also what will be paid when the plants come on line – i.e. you need to view the figure in the context of the value of money in 2023, not 2013. Add 10 years of inflation to the current wholesale price and £92.50/MWh looks a lot more palatable. Also, unlike feed-in tariffs, if the wholesale cost is above this level then the government gets the difference back. With all the inflationary pressures on wholesale prices, there is therefore a good chance that the consumer will effectively make money out of the plant. All good stuff.

What I am most pleased about however is that in all the coverage, despite the incident in Fukushima in 2011, the focus has been entirely on the price agreed. That no-one has (to my knowledge) questioned the safety and integrity of UK operators and regulators when new nuclear power plants are in the news is both right and something that makes me proud to be in that industry.

January 21, 2012

This week, green campaigners have launched a legal challenge to some aspects of legislation in an attempt to block new nuclear stations. There are two main areas of attack – governments limiting liability of the generators, and the introduction of a carbon floor price (the latter currently specific to the UK). Their challenge of course completely mis-represents the reasons why this legislation is in place. For example, on the subject of a carbon floor price Caroline Lucas, Green MP for Brighton and Hove, claims:

“The introduction of a carbon price floor is likely to result in huge windfall handouts of around £50m a year to existing nuclear generators”

I haven’t gone into the details of her claim, but I do know the history behind why the introduction of a floor price is critical to new nuclear investment, and it has nothing to do with handouts of £50m a year to generators (which, incidentally, is not a great sum in the first place. It would represent the change in revenues of existing nuclear generators if the wholesale price of electricity were to change by 0.1p per kWh, about a 2% change in the current base-load price of around 4.5p per kWh).

A little bit of history for those who aren’t familiar with the highlights of events affecting the UK energy market during the last 30 years. Electricty generation was largely a state-owned system, with the Central Electricity Generating Board (CEGB) owning and operating the power stations. In 1991, Margaret Thatcher concluded the sale of the CEGB to private investors, creating two companies – National Power and Powergen. However, during the sale process it was discovered that the existing nuclear fleet, containing a lot of old generation Magnox stations which were expensive to run and didn’t have a lot of life left in them, made the deal commercially untenable, and so all the nuclear stations were kept in public ownership under a new organisation, Nuclear Electric. This commercial PR disaster along with Chernobyl is what killed off the UK’s new nuclear build programme at the time, and why we only have one PWR today, Sizewell B.

Nuclear Electic was part-privatised in 1996, the newer design AGR and PWR stations sold off as a private company, British Energy, and the old Magnox stations retained under Magnox Electric and the Nuclear Decommissioning Authority. However, the government reformed the electricity market in 2001 with a piece of legislation called the new electricity trading arrangements. This, combined with a big dip in wholesale gas prices due to oversupply, led to a crash in the electricity price, and in 2002 British Energy essentially went bankrupt and had to be bailed out by the UK government (there were other factors, such as stations being offline, renegotiation of fuel costs and problematic business deals, but the wholesale price crash is the main trigger). The wholesale cost went down to 2p/kWh and lower, below the cost of generation. It should be pointed out that other generators also suffered from the price crash – Drax (the UK’s largest, newest and most efficient coal plant) came close to closure in 2003 because it wasn’t profitable at the time, and only a long-sighted view by investors kept it open (the plant is now very profitable).

British Energy survived with government help and was sold to EDF Energy in 2009. Now, a new build programme is looking to replace the existing nuclear fleet which is due to be largely decommissioned in the coming decade or so. However, building power plants is very expensive, in particular modern nuclear plants with advanced safety features. Therefore, investors are unwilling to commit to such a long-term project as a power station (which is expected to provide returns over a period of 60 years or more) with such high up-front costs unless they can see that their investments are secure, because it becomes too risky for the rates of return. As such, the prospect of a price crash such as that of 2001 repeating and wiping out their investment is untenable, and so long as that remains it’s unlikely that a new nuclear build programme will happen. This is the real purpose of the carbon floor price – not to give generators a £50m/year bonus (which as I’ve already stated, is small beer in the grand scheme of the industry), but to give investors the confidence to give long term commitments to new generating capacity in the UK. Without this, the industry will continue to suffer from under-investment in new capacity and we will be left with a short-term approach to new power stations, most likely further increases in the numbers of combined cycle gas turbine (CCGT) plant. There are two problems with this approach – firstly, it makes the market much more volatile to carbon fuel prices, which are unstable both in price and increasingly supply as declines in world production and increased dependence are used more and more as a political tool. Secondly, it doesn’t sort out our carbon emissions without the additional retro-fitting of carbon capture and storage technologies, which add further to the cost and fuel use and are as yet unproven on a large scale.

Faced with these realities, politicians have sensibly opted to provide the market with an instrument that guarantees a minimum carbon price, thereby making investment in nuclear and other low carbon technologies a commercial reality without otherwise subsidising them. Whether this amounts to a subsidy in name I’m not sure; it seems a bit of a grey area and I don’t have the technical knowledge to answer that question. What I do know is it seems like a credible way of delivering long term investment in low-carbon generating capacity, which can only be a good thing for the UK’s future and the environment. Few people complain about the direct subsidy of other renewable technologies including on-shore wind (except when they are taken away) which are in any case far larger in pence per kWh than any subsidisation of the nuclear industry. The fair alternative would be to remove all forms of subsidy for all forms of power generation, and apply a great deal of upward pressure politically on the carbon price. However, without the long term security of a floor price I still question the risk of such a strategy in securing the investment required.

September 23, 2008

If you were listening to Radio 4 at 7:50 this morning, you would have heard a rather firey (considering it was between two environmentalists who are theoretically therefore on roughly the same side of a debate) discussion between Caroline Lucas, who heads the Green Party, and Mark Lynas, who is a well-known activist in environmental circles. The feature came about because Mr Lynas has spoken in favour of nuclear power as something we need to decarbonise the electricity generation sector, which has resulted in him receiving a very harsh backlash from his fellow campaigners. We saw a similar reaction a few months back with George Monbiot, when he voiced his opinion that climate change was a far more important issue than the traditional opposition to nuclear power of the green movement, and that he “no longer cared” if we went nuclear or not. So why the emergent rift? And who is right?

It seems to me that Monbiot and Lynas are part of a growing cluster of people within the environmental movement who have begun to look past the traditional Chernobyl/atomic weapons opposition of the past and really think about how we can practicably meet the very tough environmental targets of the future. They have tried not to simply criticise current policy, as others have, but actually respond to the policymakers question of “well, what would you have us do?” with something implementable.

The facts are these: currently, electricity generation makes up for 20% of our energy consumption in the UK, about another 30-35% being transport and the remainder falling to space heating and industry. If either hydrogen fuel cells or electric cars/public transport is to grow in the future, this electricity demand will increase significantly. This is coupled with a projected future increase in population of the UK of about 10m by 2050, and a continued growth in the economy (a key efficiency measure used in policy making is one of emissions relative to economic output, thus a growing economy may make use of its energy more efficiently yet still have rising emissions as a nation) which will likely outstrip any marginal gains in efficiency once everyone has had their lofts insulated and pipes lagged. Nuclear power currently accounts for just under 20% of our electricity generation, with all but Sizewell B currently scheduled to come offline by 2023. Add this up, and what you get is a gaping hole in electricity generation both in the short and medium term. Unless the economy is to rapidly shrink and the lights are to go out (which would result in the quick breakdown of civilisation as we know it – not a palatable thought), this gap needs to be filled.

Anyone within the power industry will tell you that this hole will likely be plugged by gas fired power stations. While a lot more efficient than coal, there are three big problems with gas power: firstly, most of the generation cost is in the fuel, so volatile commodity prices as we have seen recently result in a very unstable wholesale price. Secondly, the UK is a net importer of gas now the North Sea fields are depleted, and relations between the UK and the big gas exporters are, shall we say, frosty. This leaves us exposed to the political whim of nations who aren’t afraid to do us some serious damage – not an ideal position to be in. And thirdly of course, this doesn’t come close to meeting our emissions reduction targets. So beyond plugging very short-term gaps in generation, an expansion of gas-generated electricity is not a very wise move, and the UK would do well to reduce this sector in the long term.

One of the main hot topics in energy at the moment is carbon capture and sequestration, or CCS. Long-term, this may well prove to be a silver bullet for the energy sector, allowing the use of plentiful supplies of cheap coal around the world to be used to generate electricity without an environmental side-effect. However, there still has yet to be a demonstration of the technology on a large commercial scale, and no-one can really give any guarantees as to how successful technically or financially this will be. To rely on CCS at this stage of saving our bacon would be more than a little risky given these facts.

The darlings of the environmental movement, efficiency gains and renewable energy, will of course play their part in the future energy mix. However, efficiency measures will only take us so far, and as outlined above growth in the economy, population and usage for electricity means that demand is likely to increase, not decrease. The renewable energy sector is currently estimated at taking a 60% share in electricity generation by 2050, but what about the other 40%? Furthermore, renewable energy requires backup for when the wind isn’t blowing etc, and this adds to the cost. The higher the percentage of renewables, the more backup you need and the more expensive it becomes. Backup is also likely to be a fossil fuel burning power station, which again doesn’t do much to help those emissions targets. Expansion of unreliable renewable energy to such a large (or even larger) share is therefore likely to be firstly very expensive, and secondly require environmentally unfriendly backup. It’s also not been demonstrated that it’s even implementable on such a scale.

Where this leaves us then is nuclear energy. Proven? Well it’s been working in this country since 1956, and with new designs is becoming ever safer, cheaper and more straightforward to decommission. Nuclear proliferation is also not possible with PWR (pressurised water reactors – the type likely to be built as the next generation of reactors) designs, as creation of weapons grade plutonium requires very frequent refuelling to prevent build up of unwanted plutonium isotopes. PWRs are operated commercially on a flat-out basis with no on-load refuelling for a lengthy period of time, making extraction of fuel for use in weapons impractical. Low carbon? Current estimates suggest a carbon emissions figure of 7-60g/kWh for nuclear (through-life cost including uranium ore mining and refinement), which is on a par with/lower than many renewable energy sources, leave alone gas at over 350g/kWh and coal at over 700g/kWh. Waste? Waste repositories are currently being constructed at several sites around the world, which is widely thought will store waste securely for thousands of years until it is no more active than the radiation from background sources. Evidence that this will succeed includes examples from nature, where active materials have been securely stored in rock for billions of years with no escape of active materials despite sub-optimal conditions. Cost? New stations are now designed with over 50 years of experience, and designed to be decomissioned safely and economically. Experience with legacy equipment should not be allowed to be confused with what is being proposed for the future. Fuel costs are also around 10% of operating costs, which provides much more stability in costs. Studies show that an appropriate mix of nuclear power is projected to be significantly cheaper than increasing renewable energy usage beyond the 60% planned level by 2050. Reliability of supply? Newer designs have excellent load factor performance.

So, the next time you hear Caroline Lucas tell you how expensive nuclear power is compared to other technologies like renewables, how we don’t need it because we can all save energy usage by efficiency measures, how dangerous it is because of nuclear wastes and the risk of proliferation, take a moment to consider her claims and do some research for yourselves instead of believing the rhetoric. And realise just how much twaddle her and her ilk talk.

May 25, 2006

Following an announcement nearly a year ago that a site in France has been chosen for ITER (International Thermonuclear Experimental Reactor), the news came yesterday lunchtime that the go–ahead has been given for work to start. This represents a long term security for clean energy supply, and is the successor to the JET fusion reactor in Culham, Oxford. It is expected for work to begin in 2007 and for construction to take 8 years. If all goes to plan we should see a full scale demonstration reactor being set up by 2040, with commercial availability around 2050. About time I say. Sequestration of clean coal won't keep us going forever, and gas is fast running out. Other nuclear fission alternatives, such as fast breeder reactors or thorium reactors, aren't yet here either and would I suspect prove unpopular with the public, just as conventional fission is currently. I even doubt the inherently fail–safe pebble bed systems being developed and built in South Africa will prove acceptable to the NIMBY brigade.

For those who are unaware with the background, Fusion is a nuclear process involving the joining of small atoms as opposed to current nuclear technology based on fission, which splits large atoms into smaller ones. For anyone who wants the physics, it releases energy because atomic stability (measured in binding energy per nucleon) increases for small elements up to Iron, which is the most stable element in nuclear terms. Beyond this, binding energy per nucleon decreases (due to electrostatic repulsion from protons in the nucleus becoming more significant than the powerful but short–ranged strong nuclear force). Reactors on earth use two hydrogen isotopes (usually deuterium and tritium) to make a helium nucleus and a free neutron, which most of the energy goes to. The high speed neutron is then absorbed by a blanket around the reactor, and heats up. This can then be converted to steam and power extracted from turbines. Radioactive products from the reactor are only the helium atoms, which have a radioactive half–life of 10 minutes. In order to overcome the strong electrostatic repulsion of two protons, immense energy is required, and so temeratures in excess of 100 million degrees centigrade have to be reached, with up to 300 million degrees reached at JET. The process takes place in a vacuum, and obviously at these temperatures the material cannot come into contact with any non–reaction material so is magnetically confined. In any case, contact between the reaction material and the reactor walls (or any impurities in the vacuum) would result in massive temperature loss and bolts shooting through the reactor pressure vessel. Because the products have such a short half–life, and because any failure of the vacuum or magnetic confinement results in immediate massive temperature loss and therefore reaction ceasing, the process is inherently safe and there is no possibility of the reaction becoming unstoppable.

With regards to fuel availability, deuterium is readily extractable from water (which is not exactly in short supply), and enough deuterium exists in 500 litres of seawater to supply a person's electricity needs for a lifetime. One kilogram of fuel for a fusion reactor has the same energy content as 10,000 tonnes of fossil fuel.

So basically, the future of energy supply draws ever closer. Watch this space!

October 14, 2005

Chris recently raised a debate on energy sources and the future of gas supplies. One of the main points that seem to have spun off from this is rather predictably the nuclear debate. In this post in response to some comments, I will attempt to outline why I feel that nuclear fission is the most viable stop–gap until fusion power can be fully developed to commercial levels hopefully sometime in the middle of this century.

The first point I wish to make is to alleviate a public misconception about nuclear fission – the association of nuclear power generation with nuclear weapons and explosions. Now I know that many people who will be reading this will already be well informed on this so if you don't want a basic talk through the differences then skip the next couple of paragraphs. Now, in order to understand why nuclear reactors cannot explode it is necessary to understand some basic things about nuclear reactions. Fission (the splitting of atoms to create smaller atoms and release energy) releases energy because unstable nuclei (uranium 235 in power generation) split to form two stable nuclei, releasing energy because of the difference in something called the binding energy per nucleon between the unstable and stable nuclei. The reaction is initiated by the absorption by the uranium nucleus of a neutron. The fission process for uranium 235 releases on average 2.4 neutrons per fission reaction (called the reproduction rate), so you can see that in theory the reaction rate would increase with each fission reaction starting another 2.4 fission reactions. This is what happens in a nuclear explosion – a neutron source is put into contact with a mass of fuel greater than the critical mass (minimum needed to sustain a reaction) and the reproduction rate explodes at very high rates. The usual fuel for this is Plutonium 239.

However, naturally occurring uranium is only 0.7% Uranium 235, with the rest being a stable isotope Uranium 238. Thus, most of the neutrons are absorbed by this and do not initiate further reactions, therefore the reproduction rate is much less than one and a chain reaction does not occur. For power generation the target reproduction rate is obviously exactly 1, because then the reaction is happening at a constant rate. In order for this to happen, we first enrich natural uranium to higher levels of Uranium 235 so that a chain reaction can occur (but nothing like the enrichment levels in nuclear weapons). Furthermore, we utilise control rods (usually graphite) to absorb excess neutrons as well, which we can move in and out of the nuclear fuel to control the reproduction ratio to exactly 1. The reaction is very stable and simply controlled, and even if the control rods are completely removed the reaction will not explode out of control because the fuel is not rich enough. Instead, what happens is something like happened at Chernobyl, where the control rods were almost completely removed in an experiment where the safety features were disabled and the reaction rate increased dramatically, causing the temperature to rise and the reactor to fail. This incident was a meltdown, not a nuclear explosion. The whole incident was a catalogue of errors which went right back to the design of the reactor itself, and would never happen in a more modern reactor. For a more in-depth look, check out this site. Essentially, it was a catastrophic operator error incident that actually caused the reactor to fail, something I would not unfairly liken to trying to get a child to loop the loop in a 747 jet (in case you're wondering, such a thing is technically impossible – either the wings would fall off or the plane would stall).

There are three other concerns raised by most members of the public – costs, long term waste disposal and leak risks from accidents or terrorist attacks. Long term waste disposal is perhaps the single largest of these. High level waste is actually produced in very small quantities, and is difficult to deal with. The best idea I have seen to date is a system involving a facility called a geological repository. The waste is safely buried in a stable rock formation deep underground in a deserted area, a long way from any water tables or risks of geological movement. This is a very high initial capital cost solution in one respect, but overall I believe the economies of scale of having a one–off disposal cost at a site that could hold many thousands of tonnes of nuclear waste would pay off very well. The threat of radiation is solved by the natural barrier of hundreds of metres of rock, and let us not forget that the earth itself is highly radioactive underground. The best place to put the stuff is back where it came from, where it can't hurt anybody and can't go anywhere. If anyone has reasons as to why this would be unsafe, please let me know. To give you an idea of quantities, low level waste accounts for 90% of the volume of radioactive material, intermediate level waste a further 7% and high level waste 3%. This equates to about 3 cubic metres a year for a typical large nuclear reactor. Compare this to the hundreds of thousands of tonnes of CO2 a comparative fossil fuel station emits, and we start to see an argument stacking up in favour of nuclear power. High level waste is solidified by mixing with glass–forming compounds, which are then poured into stainless steel containers and welded shut. After a period of approximately 40 years (during which these "vitrified" wastes are held in dry concrete casks or underwater in specialised ponds), the material has dropped to 0.1% of its initial activity. It is then suitable for storage deep underground. In the US, a facility in Nevada for long term storage has been costed at about 0.1 cents per kWh, which is comparatively low to the consumer price, which is in the order of 100 times this, thus the long term storage represents about 1% of cost.

Only about 3% of spent fuel from a reactor is actually waste. In Europe (primarily at Sellafied in the UK and a similar site in France), most fuel is reprocessed with the 3% waste removed, and the remaining 97% returned to rods to be used again as fuel. In this way, we both extend our fuel supplies dramatically and at the same time cut down on the amount of high level waste that requires burial. For more information on wastes check out this site (my specific data on wastes has largely been sourced from this article).

It's worth mentioning as an aside how long known uranium ore supplies would last. It is estimated currently in the 100's of years (although I couldn't find specific data); and that is without fuel reprocessing and the use of breeder reactors, which would increase reserves by a factor of 60–70. In short, fuel supply is not a problem for the foreseeable future of nuclear power.

Cost issues are also another commonly raised concern, with many opponents to nuclear power arguing that decommissioning is not taken into account and is hugely expensive. I already gave some ballpark figures for long term storage costs for nuclear wastes (although this is the storage cost itself; the solidification process and 40 year storage period is not costed into this). Exact costs are hard to find and calculate, as of course it is a long term decommissioning process, and varies depending on reactor type. Furthermore, there are multiple options to take in the decommissioning process, and the whole task itself is still one which we are gaining in experience all the time, making long term reductions in costs even harder to calculate. Because of this complexity, facts are often misreported and twisted by opponents of nuclear power. At present, nuclear generators in the US are collecting between 0.1 and 0.2 cents per kWh to cover decommissioning costs, again not a huge sum. This site explains decommissioning including costing in much more depth that I will go into here, but suffice to say that if you want to know more about decommissioning then it's a pretty good introduction. Another cost analysis is available from the same website here if you wish to compare generating costs with rivals.

So what about safety? Well again I refer you to my favourite website for more information, but I'll summarise here. All modern nuclear power stations must have containment systems built around the reactor (Chernobyl did not have this). Current standards state that reactors must be built with a one in 10,000 year core damage frequency, however modern designs exceed this by a factor of between 10 and 100. Designs in the next decade are likely to see this increase by a factor of 10 again. In 12,000 years of combined reactor operation, there have been two major accidents; one at 3 mile island in 1979 where the leak was contained by the built in containment around the reactor, and the Chernobyl incident discussed previously. Other factors need to be considered against other industries too. For example, every year around 1,000 people die mining coal. Long term damage to the environment of CO2 and the health implications that this will cause to mankind – increased environmental disasters killing many people etc etc. Quoting directly from the above site, optimum safety is achieved by:
"

redundant and diverse systems to detect problems, control damage to the fuel and prevent significant radioactive releases

provision to confine the effects of serious fuel damage to the plant itself

The safety systems include a series of physical barriers between the radioactive reactor core and the environment, the provision of multiple safety systems, each with backup and designed to accommodate human error. Safety systems account for about one quarter of the capital cost of such reactors."

Other safety features of nuclear power stations include things like automatic shutdown in periods of seismic activity. Post the WTC attacks, various studies have concluded that nuclear power installations are amongst the safest civil buildings and most resistant to terrorist attack. Even when models were generated of the largest civil aviation aircraft impacting at high speed while fully fuelled, there was no perceived risk of a breach to either the reactor fuel or storage for wastes, or transport casks.

It's also worth putting the severity of nuclear incidents into perspective. In the case of the Chernobyl disaster (by far the most catastrophic on record), the incident killed 31 people, 28 of which died within weeks of radiation exposure. It also caused radiation sickness in between 200–300 emergency workers. About 130,000 people received doses above internationally accepted limits. About 800 cases of thyroid cancer in children have been linked to the incident, of which most have been cured, around 10 have been fatal. No detected increase in other cancers has yet shown itself, although there is an expected rise. The WHO is still closely monitoring the after–effects to this day. We can conclude that while a terrible and tragic incident (and even more importantly, avoidable), it's hardly a doomsday end of the world type scenario as is often predicted by those who wish to over–dramatise the effect of nuclear catastrophe to strengthen their anti–nuclear case.

Perhaps the most pertinent question of all though remains – do we need it? Well, the UK has a base demand of approximately 47GW of electricity. This has to be generated somehow. By the government's own targets, even by 2050 so–called renewable energy sources, which are comparatively new and untested on the scales necessary to satisfy such base loads, potentially expensive and unreliable and also require backup generation, will only satisfy 60% of UK demand, and compared to many other parts of the world this is a pretty high target, although not the highest. In the meantime, where are we going to get our energy? Renewables cannot satisfy the interim demand, and in my judgement cannot meet long term demand and expansion either, certainly not without large areas put down to expensive wind farms or damming off rivers etc. Biomass schemes are new, not accelerating in growth fast enough and in any case are unlikely to be able to sate our generating demands (although I believe the future of transport lies in bio–fuels, I may make a post on this in the near future). Our options remain to be nuclear or further depletion of fossil fuels, along with associated CO2 emissions. These are the only choices for the short to medium term, regardless of what alternatives you might have faith in. I have put the case for nuclear here. What's your choice?